A zublin



Feb. 14, 1956 J. A. ZUBLIN 2,734,720

APPARATUS FOR DRILLING WELLS WITH ORIENTED CURVED BORES OF LARGE RADII Filed Dec. 30, 1952 2 Sheets-Sheet l 6 #5 ,/M. Z flm Jaim A. ZzLbZI/'n/ ATTORNEYl 2,734,720 ENTED 2 Sheets-Sheet 2 A. ZUBLIN APPARATUS FOR DRILLING WELLS WITH ORI CURVED BORES OF' LARGE RADII Filed Dec. 30, 1952 Feb. 14, 1956 INVENTOR Jlm A. Zal/17h21@ BY M114 Qu r ATTORNEYS A .0 /7 t l United States Patent APPARATUS FOR DRILLING WELLS WITH ORI- ENTED CURVED BORES LARGE RADII .lohn A. Zublin, Los Angeles, Calif. Application December 30, 1952, Serial No. 328,679

4 Claims. (Cl. Z55-1.6)

The present invention relates to a method and apparatus for drilling oil Wells with oriented curved bores of large radii. lt is the purpose and object of the invention to drilling of a dellecting bore 'in a given azimuth is apparent.

It is the purpose and object of the present invention to provide a method and apparatus by which such a deflecting bore may be produced through conventional rotary drilling technique as a direct continuation of an initiated vertical well bore.

The present invention is not concerned with the production of curved deviating bores of small radii, such as drain holes drilled directly from a vertical well bore laterally into the producing formation, but is rather concerned with the production of a deflecting bore. as a continuation of an initially straight well bore, in the original drilling of which the bore is dellected in a curved path of large radius of the order of 1,000 to 2,000 feet.

In the prior art practice of drilling dellecting bores, the expedient of using whipstocksv has been largely resorted to. Generally speaking, the tubular drill strings employed in rotary drilling have sulfcient inherent flexibility to permit of their deviation from the vertical in Van amount approximating about three degrees per hundred feet of length of drilling string. Again speaking generally, whipstocks set in a vertical well bore forvthe purpose of causing a deilection of the drill bit usuallycontemplate a deilection from the Vertical of from around three degrees to five degrees. In practice it has been found that when drilling a deecting bore through the medium of the Whipstock, the drill string, after it passes the whipstock, tends vto follow the path of least resistance and return to a straight line under the inlluence of gravity. Because of this inherent tendency of the rotary drill string to follow the path of least resistance it hasbeen the prior art practice in the drilling of detlecting bores through the use of whipstocks to drill a limited distance beyond the point of setting ofa4 given whipstock; to then withdraw the drill string and bit from the Well bore and set another whipstock at the lower depth to which the deflecting bore had been drilled, this procedure being repeated throughout the drilling of the deflecting bore. Such practice has entailed the necessity for a complete round-trip each time a'whipstock is set. Each round-trip andeach setting of the whipstockentails hazards that, quite apart fromthe sheer loss of Vtime involved,` render the drillingof deflecting bores of large radii very costly.

It is the purpose and object of the present inventionto provide va greatly simplied method and apparatus for use of whipstocks and complete the drilling of the defleeting bore, or even a series of deiiecting bores, on one round-trip of the drilling equipment'.

More specifically it is the purpose and object of the invention to provide a method and apparatus for initiating and continuing the drilling of a deilecting bore, at substantially the same xed radius, suiciently large to lie within the limits of inherent flexibility of the conventional rotary drill string.

From an apparatus stand-point, the purpose and object of the invention is to provide a unit suspendable from the lower end of a rotary drill string susceptible of manipulation in such a manner as to effect the initiation and con- .tinued drilling of a curved deecting bore of large radius without the use of other elements or instrumentalities than those suspended from and carried by and insertable into the well bore through the medium of a conventional rotary drill string.

By the expression curved bores of large radii as employed in this application, it is intended to identify and define vdegrees of curvature attainable through the inherent -exibility of a normal rotary drill string. Generally speaking, the radii of deilecting bores, in the drilling of which the present invention is addressed, lie within the'limits of 1,000 to 3,000 feet. The further purposes and objects of the invention will become apparent as the description proceeds which willy be given in connection with the accompanying drawings forming a part hereof, and in which:

Figure l is a fragmentary view and side elevation with parts broken away and illustrating a position of a drilling unit suitable for practicing the method and exemplifying the apparatus of the present invention.

Figure 2 isa detailed cross-sectional view illustrating the manner in which the deflecting force is applied to the drilling unit.

Figure 3 is a detailed cross-sectional view taken on the line 3--3 of Figure r2.

Figure `4 is a detailed cross-sectional view taken on the line lf-4 of Figure 2. l

Figure 5 is a detailedcross-sectional view taken on the v line'5.-5 of Figure 2.

Figure-6 is a detailed cross-sectional view through the clutch mechanism illustrating operational features of the apparatus, and

Figure 7 is a detailed cross-sectional view illustrating they manner in which the drilling unit may be suspended from a conventional rotary drill string.

Referring to lFigure 1, a conventional hollow rotaryl drill string is indicated at 10 which is adapted to extend to the surface of the Well and be rotated by the conventional rotary equipment. Drilling uicl is adapted to be passed down and through the drill string 10 from the lower end of which is suspended a unit assembly embracing an inner tubular rotary drive member 11 which carries the bit 12 at its lower end so that rotation of the rotary drill string 10 and the rotary tubular drive member 11 will effect a positive rotation of the bit 12. Surrounding the rotary drivememberV 11 is an elongated sleeve 13, the

` upper-'end of which is threadably engaged at 14 in a collar 15 carrying anti-friction means 16 for facilitating free rotation of -the tubulardrive member 11 within the sleeve 17 is rigidly secured to the sleeve 13 and'acts to center mally be moved.

the same'in the well bore.

The collar 17 in reality acts as a fulcrum about which the portions of theunit below the collar 17vcould no r- "At a point intermediate Patented Feb. 14, 1956' theA collar 17 and .the bit unit has its upper end securedas indicated`at'125`" to'the.

anchor collar 19 oppositethe gripping/teeth 26' thereof; The lower end ofA the leaf-spring 24S-is secured as -indicated at 27 to the slidable collar 211 opposite thegrippingfteeth ZS'thereof. Stop members 29are` carried by the sleeve 13l to limit the upper movement of: the slidable collar.21l

on the sleeve 13. Secured tothe lower end .ofthe sleeve 13 by the threaded connections 29' is theupperrnemb'er 300i the two-member clutch,.the` lower member'31; of which is secured to and carried by the inner rotary drive member 11.

string 10, the frictional resistanceoieredA by the VcollarV 17'andthe spring 24 engaged withthe. well. bore 'wall and the weight of attendant mountings carriedby. the-.outer sleeve 13, will hold the sleeve 13, permitting limitedvertical movement of the inner drive memberfll and engagement of the clutch members 30 and-31y to' permit concurrent rotation of the inner drive member 11 and'thefsleeve 13 to facilitate orientation of the sleeve 13 andV insure deilection of the bit 12 in a desiredazimuth.'l It willlbe appreciated that'as the drilling of thefdeiiecting borecontinues the spring 24 tends to force the collars19z and 21 toward the side of the bore of smallestradius. Whenthe teeth 26 and 2S of collars 19 and 2.1 are presse'dagainst the wall of the deiiecting bore the degree ofdeliection' will become stable and the bore will continuetwith substantially the same radius. The spring 24`continues to maintain proper friction between'thev collars- 19," 21 and thewall of the well bore whereby the member 13 isV held against rotation as it advances into the borel- Onlythe closing of the clutch members 30 and 31 ywith forcedrotation of member 13 will vary the azimuth ofthe deecting bore. lt will also be appreciated that the weight of the sleeve 13 and parts carried thereby is normally suciently in excess of the frictional resistance or dragcreated by spring 24 and the ribs on collars 17, 19 and 21 engaging with the well bore such that the sleeve will normally'move along with the drill collar 11 and drillbit 12.

By reference to Fig. l, it will be observed that the drilling unit has three points of contact with the` well bore. Point A being the contact of the upper collar 17 with the well bore; point B being the contact of the drill bit 12 with the well bore; and point C being thercontact of the spring 24 with the well bore. The bit T12-rotates andits sharp teeth cut sidewardly into the wellbore' under the force supplied through the mediumof'the spring 24.

Thus after a' few rotationsof the drillstring'withJthe parts' in the `position shown in Fig. l, the bit initiates the drilling sidewardly under the force of the spring 24. Theb'it is lowered simultaneously with this sideward drilling tendency with the result that there is initiated the drilling of a curved bore of large radius determined-by the threepoint Contact of the unit with the well bore. In the illustrated embodiment the distance between pointsA and B is approximately 14 feet. spring 24 through its area of engagement with the well bore wall is of the order of from 100 lbs; to 1,000 lbs. With this construction a deecting bore having aradius of curvature of about 1,900 feet can be produced vand the complete deecting bore drilled on one round-trip ofthe drilling unit into and out of the well.

It will be understood that the etectivepressure applied to the bit will depend somewhat on the-'relative'location' of the 'points A, B, and C, and that "by'the variation of the relationship ofthe points A, B; and'C, andthe degree of pressure applied by the spring 24 at thepointC, the

A: heavy leaf-spring: 24?

They spring 32 normally urges-the.' clutch members 30 and 31 toward disengaged position. When however an upward pullis exerted on. the rotarly drillV The total pressure applied by the 4. degree ofv dellection of the bit can be quite accurately controlled within the limits `of elasticity of the rotary drill string 10.

While the invention is primarily intended to effect the drilling of a deflecting bore as a continuation of an initiated vertical bore, it is possible to take oi from a vertical bore that has been previously drilled with a dellecting bore in a predetermined azimuth. Indeed it is even possible t0 drill asecond deecting bore after a rst bore in a given azimuth has beendrilled. A slight-upward pull on the drill string 10 with limited partial rotation will effect engagement ofA theclutch members 30 and 31, following which the unit may be oriented to a new azimuth.

Having thus described my invention, what I claim is:

1. Apparatus for controlling the direction and extent of deviation of a well bore by the rotary drilling method comprising an elongated relatively inilexible tubular section, an elongated drill collar rotatably mounted in said tubular section, a drill bit carried-at the lower end of and rotatable with said drill/collar, means at` the upper end ofsaid drill collar for connectingsame tofthe lower end ofa'rotar-y drill stringlforv rotationl therewith, a collar rigidly securedto said tubular sectionand having outwardly projecting ribs engageable with the wellrbore wall to provide a fulcrum about which said tubular section canpivot, and well borek engaging deiiecting means carried.g by'said tubular 'section at a point spaced from said collar acting to urge said inflexible tubular section and said drillfrbit to' pivot about said collar ini a predetermined radial direction'.

2j Apparatus as recited in-clairn 1 wherein said collar is-.rn'ounted atthe upper end of said tubular section, and

said wellbore engaging deflecting means iscarried by said tubularI sectionat a point spaced below said collar.

3. Apparatusy forcon'trollingfthe direction-and extent of devia'tionvof.aIwell-bore by the rotar-y drilling method comprising an elongated relatively inflexible tubular section, an-elongate'ddrill collar rotatably mounted in said tubular section and -capable of limited lonigtudinal movement relative to said tubular section, interengaging clutch elements-carried by saidtubular section and said drill collar respectively, means-normally holding said clutch elements indisengagedposition while permitting engagemerit' ofi said clutch elements upon limitedlongitudinal movementof said drill collarfwithin said tubular section, ai-drill bit carried at-thelower end of and rotatable with said drill collar, means at the upper end of said drill collar for connectingsame tov the lower end of a rotary drill string for rotation therewith and whereby said drill collar may be vm'oved longitudinally relative to said'tubular sectionby lifting of the drill string vfor'engagement of said clutch elements, a collar rigidlysecured to said tubular section and having outwardly projecting ribs engageable withthe wellbore wall to provide a fulcrum about which said.tubularsection-canpivot, and well'bore engaging defleeting-means.carriedV by said tubular section at a point spaced from said collar acting to urge said inexible tubular section and said drill bit to pivot about said collar in a predetermined radial direction. i

4. Apparatus'as'recited in claim 3 wherein said collar ismounted-at the upper` endl of said tubular section and said well bore engaging deflecting means includes a wall engaging spring carried-by said tubular section at a point intermediate the ends of said tubular section.

References Cited in the Yiile of this patent UNITED STATES PATENTS 2,072,320 Thomas` Mar. 2, 1937 2,167,194 Anderson July 25, 1939 2,319,236 Isaacks et al.l May 18, 1943 2,32959'7" Diehl et al. n -Sept' 14, 1943 2,589,534v Buttolph Mar. 18, 1952 643,859 Brown Junek 30, 1953 

